Water tube boiler



Patented Aug. 8, 1933 V} UNITED STA signor to i the Firm Sulzer. Freres Socit Anonyme, Winterthur, Switzerland Application August 18, 1931, Serial No. 557,828,;

and in Switzerland and Germany August 19,

This invention relates to water tube boilers of the kind comprising a lower drum communicating with each of two or more upper drums through upflow and downflow tubes arranged vertically or at aqsteep; angle to the horizontal.

Boilers of this type have been open to the disadvantage that under certain conditions of load and heat supply reversal of the circulation of the working medium tends to take place and local circulationis liable to occur in the nests of tubes thereby impairing efilcient circulation of the fluid.

According to the present invention not only do some at least of the upflow tubes irom the lower drum open into the steam space of one upper drum which communicates with the lower drum throughdownfiow tubes, but also some at least'of the upflow tubes from the same lower drum open into the steam space of the seconduupper drum whose water space communicates in known manner with the lower drumithrough downflow tubes, so that when the boiler is steaming at a high rate, the rate of evaporation from the surface of the water in the upper drums is kept low and circulation through the tubes inthe same" direction. is'ensured. I t

One construction of boiler according to the invention is illustrated by way of example in the accompanying drawing and comprises a lower drum 1, and two upper drums 2" and 3 The lower drum 1 communicates with the 'upper drum-2 through upflow tubes 4 some of which open into the steam space 5 whilst the remainder open into the water space as shown. The drum 2 also 315; communicates with the lower drum 1 through downilow tubes 6 which are protected from the direct action of the hot gases by walls '7.

The lower drum is similarly in communication with the upper drum 3 through upflow tubes 8 some of which open into'the steam space 9 and the remainder into the space normally, occupied by water. 7 The upper drum 3 in addition comv municates with the lower drum through down-' flow tubes 10, baille plates Hand 12 being prov vided adjacent to the tubes 8 and 10 respectively. The steam spaces 5-and 9 of the drums 2', 3 communicate through tubes 13, the water spaces of these two upper drums communicating through tubes 14. Walls 15 and 16 are provided for the purpose of protecting the upper parts of' 'the tubes from the direct action of the hot gases, additional tubes 17 being arranged-below the wall 16 and serving as additional communication between the water spaces of the drums 2, 3.

An additional baffle plate 18 is arranged as 5 claims. (or. 122-302) shown adjacent to theinner tubes 4 and superheating tubes 19 are disposed in the spaceibetween the baflie plate 18 and additional upflow tubes 20 communicating between the lower drum 1 and the upper drum 2 and disposed adjacent to one of theprotectingwalls 7-. v The super-heater 19 communicates withthe steam space 9 of the upper drum3 through a pipe, 21', a pipe 22 con-,-

ducting the steam to the point of consumption.

The circulation of theworking medium is indicated by the arrows shown in full lines and the path followed by the combusition gases is indicated by the arrows shown in chain lines from which it will 'be seen that circulation of the me-. dium'between the lower drum 4 and each of the upper drums 2 and 3 takes place in one direction only and that greaterpart of the down flow tubes 6 is protected from the direct action of thehot gases not only by the walls? butin addition by the upflow tubes 20. I s i Itwill be understood that while the invention has been described as'applied to a boiler having a r tion.

g I claim:

1. Vertical water-tube boiler comprising at least two upper drums belonging to a joint lower drum and partly filled with water, characterized in that the upflow tubes leading from the'lower drum to the upper drums terminate partly in the steam spaceof the upper drums, and that down- ,ilowftubes are'provided leading from every upper drum to the lower drumand situated behind the upflow tubes of the respectiveupper drum, the downflow'tubes situated in front of the upflow tubes of the second upper drum being shielded from the action of flue gases by being insulated on the side of the upper drum. 7 w s 1 2. In awater tube boiler, in combination a furnace, a lower drum, a plurality of upper drums,

one in front of the other, upflow tubes connecting said lowerrdrum to each of said upper drums, some at least of said upfiowtubes leading to each upper drum opening into the steam spaces of said upper drums, downflow tubes Vconnectingfthe water space of each of said upper drums to said 7 lower drum, walls extending from the front upper drum and surrounding the greater part of "the length of said downflow tubes lying nearer said furnace and serving to protect said tubes from direct action of the hot gases of said furnace, tubes connecting the steam spaces of said upper drums and tubes connecting the water spaces of said upper drums. V V

3. In a water tube boiler, in combination a furnace, a lower drum, a plurality of upper drums,

one in front of the other, upfiow tubes connecting said lower drum to each of said upper drums, some at least of said upfiow tubes leading to each upper drum opening into the steam spaces of said upper drums, downfiow tubes connecting the water space of each of said upper drums to said lower drum, walls extending from the front upper drum and surrounding the greater part of the length of said downfiow tubes lying nearer said furnace and serving to protect said tubes from direct action of the hot gases of said furnace, a baffle plate between said protected downflow tubes and said upflow tubes lying nearer said furnace, a second baffle plate between said upfiow tubes lying further away from said furnaceand said downflow tubes furthest away from said furnace, a third baille plat-e behind said downflow tubes lying furthest .away from said furnace, tubes connecting the steam spaces of said upper drums, tubes connecting the water spaces of said upper drums, and a bafiie plate beneath said tubes connecting the water spaces of said upper drums.

4. In a water tubeboiler, in combination a furnace, a lower drum, a plurality of upper drums, one in front of the-other, upfiow tubes connecting said lower drum to each of said upper drums, some at least of said upfiow tubes leading to each upper drum opening into the steam spaces of said upper drums, downflowtubes connecting the water space of each of said upper drums to said lower drum, walls extending from the front upper drum and surrounding the greater part of the length of said downi'low tubes lying nearer'said furnace and serving to protect said tubes from direct action of the hot gases of said furnace, a baflle plate between said protected downfiowtubes and said upfiow tubes lying nearer saidfurnace, super-heater tubes {arranged ing the water spaces of said upper drums and a baflie plate beneath said tubes connecting the Water spaces'of said upper drums.

5, In awater tube boiler, in combination a furnace, a lower drum, a plurality of upper drums, one in front of the other, upfiow tubes connecting said lower drum to each of said upper drums, some at least of said upfiow tubes leading to each upper drum opening into the steam spaces of said upper drums, downflow tubes connecting the water space of each of said upper drums. to said lower drum, walls extending from the front upper drum and surrounding the greater part of theglength of said downflow tubes lying nearer said furnace and serving to protect said tubes from direct action of the hot'gases of said furnace, a baffle plate between said protected downi'low tubes and said upfiow tubes lying nearer said furnace, superheater tubes arranged between said bafile plate and said protected downflow tubes, additional upfiow tubes between said protected downflow tubes and said super-heater tubes, a tube connecting said super-heater tubes to one of said upper drums, a second baiiie plate between said upfiow tubes lying further away 110 from said furnace and said down-flow tubes furthest away from said furnace, a third baffle plate behind said downiiow tubes lying furthest away from said furnace,'tubes connecting the steam spaces of said upper drums, tubes connecting the 1'15 water spaces of said upper drums, a bafiie plate beneath said tubes connecting the water spaces of said; upper drums and additional tubes" bee neathsaid last mentioned bafiie plates connecting the'water spaces of said upper drums.

' ADALBE RT SCHMIDLI. 

